Interesting you mention that llama, just from what I have observed, they added some FPS features such as a dodge roll (will be essential in combat), no global cooldown feature for instant cast abilities (allowing you to chain combo buttons as fast as you physically can do it).

They've apparently designed it so it is less of a "rotation" system like WoW / Swtor have and more of a reaction depending on what your enemy does. A class like the theif is very resource intensive (initiative bar), and certain skills take half to 1/3 of that bar - so you can't just spam all your abilities to kill someone.

I hope that combat feels more interactive, but I guess we'll wait and see based on how the weekend goes.